#include <iostream>

using namespace std;

void test();
void test1();
void test2();

int main()
{
    test();
    test1();
    test2();
    return 0;
}

void test()
{
    cout << "===================" << endl;
    int a = 10, b = 20, temp;
    cout << "a=" << a << ",b=" << b << endl;
    temp = a;
    a = b;
    b = temp;
    cout << "a=" << a << ",b=" << b << endl;
}
void test1()
{
    cout << "===================" << endl;
    int a = 10, b = 20;
    cout << "a=" << a << ",b=" << b << endl;
    a = a + b;
    b = a - b;
    a = a - b;
    cout << "a=" << a << ",b=" << b << endl;
}
void test2()
{
    cout << "===================" << endl;
    int a = 10, b = 20;
    cout << "a=" << a << ",b=" << b << endl;
    a = a ^ b;
    b = a ^ b;
    a = a ^ b;
    cout << "a=" << a << ",b=" << b << endl;
}